The start_date is the date at which the tap will begin pulling data. The
Listrak API uses a form of HTTP Basic Authentication, meaning the username
and password you use to login to Listrak must be provided.

Stream Dependencies

You must select the lists stream in order for any others to sync. The
messages and subscribed_contacts contacts stream depend directly on the
data fetched by the lists stream.

Additionally, the messages stream must be selected for any of the message_*
streams to function, as those streams depend on the data fetched by messages.

lists and messages are selected by default.

Notes on Bookmarking

Due to the dependency structure of the Listrak API, we cannot avoid pulling all
lists and messages during every run of the tap. An example of why: a
message that was created in 2015 could theoretically have been opened by a
contact in 2017.

This means if you have a very large number of messages, they will be synced
every run. You could avoid this by running an initial sync using an older
start_date in your config and then update start_date to something more
recent. This will result in only messages created since start_date to be
synced, but it also means any message_sends, message_opens, etc. for
messages created before this start_date will not be synced.